We think positively about the actor because he played a hero, or the actress because she was made up to look incredibly beautiful, and assume that they therefore have deep knowledge about car engines or anti-wrinkle cream.

ECONOMIST: Idea

The women who sell wrinkle cream and recruit others to sell it tend to be women who stay home to raise their children and are seeking an outside-the-home identity as much as income, says Lori Bush, the company's president and chief executive.

WSJ: Work and Family: When Moms Need a Business Trip